A method for operating a transmission device, in particular a nine-speed transmission, is known from the unpublished DE 10 2013 202 707.9 or the unpublished DE 10 2013 202 708.7 of the applicant, for which, through a sensor device upstream of a throttle device, which is connected to a transmission area essentially featuring ambient pressure, a value of a pressure signal corresponding to the operating pressure of a positive-locking shifting element of the transmission device can be determined. Upon exceeding a threshold value of the pressure signal, currently in the area of the positive-locking shifting element, a change in operating state is determined, and, upon falling short of an additional threshold value of the pressure signal, the reaching of the requested operating state is established.
The sensor device is designed as a so-called “absolute pressure sensor,” through which the absolute value of the pressure signal can be determined, which value arises as a measured value from the sum of the existing ambient pressure and the relative amount of pressure resulting from the operating pressure applied at the positive-locking shifting element. Thereby, the relative amount of pressure is nearly constant during a change in operating state of the positive-locking shifting element, while the ambient pressure varies, depending on the operating state, due to the weather and depending on the current altitude currently traveled on by a vehicle designed with the transmission device. For this reason, the start of the change in operating state determined by the threshold value varies in the area of the positive-locking shifting element and the established point in time at which the positive-locking shifting element reaches the requested operating state. Therefore, depending on this, the functions of a transmission device that are carried out are initiated too late or too early, which, during unfavorable operating state curves, can adversely affect driving comfort.
As such, this invention is directed to a method that is able to be carried out with a low degree of control and adjusting effort for operating a transmission device, in particular a nine-speed transmission, with which a high degree of driving comfort is possible.